Electric water heater



Feb. 12, 1935. Q z 1,990,790

ELECTRIC WATER HEATER Filed Sept. 22, 1932 2 Sheets-Sheet 1 10d 17 11 w17 40w 15'- 70125 Aifior 0e ys m-M (MZZMW/ Feb. 12, 1935. o. A, LENZELECTRIC WATER HEATER Filed Sept, 22, 1937. 2 Sheets-Sheet 2 PatentedFeb. 12, 1935 UNITED STATES PATENT OFFICE 3 Claims.

My invention relates to electric water heaters and particularly toheaters wherein electricity passes from one electrode to another throughthe liquid being heated,

It is an object of my invention to provide a novel, simple, compact, andinexpensive heater of the class indicated wherein none of the parts aresusceptible of burning out, even if the device remains connected to asource of electrical energy after substantially all of the water in thedevice has evaporated.

Another object is to provide such a heater wherein water may be heatedto its boiling point with great rapidity and wherein automatic meansinvolving no moving parts is provided to constantly maintain watertherein substantially at a boiling temperature or steam therein at acertain pressure and to regulate the consumption of electrical energy toa value only sufficient to maintain water at such temperature or thesteam at such pressure.

These and other objects and advantages of the present invention willmore fully appear from the following description, made in connectionwith the accompanying drawings, wherein like reference characters referto the same or similar parts throughout the various views, and, in whichFig. 1 is a top view of my invention with the cover thereof removed;

Fig. 2 is a longitudinal vertical sectional view of my invention takenalong the line 2-2 of Fig. 1, but with the cover in place;

Fig. 3 is a vertical cross sectional view taken along the line 3-3 ofFig. 1, but with the cover in place;

Fig. 4 is a vertical cross sectional view of another form of myinvention; and

Fig. 5 is a vertical cross sectional view of still another form of myinvention.

Referring to Figs. 1. 2, and 3 of the drawings, an open toppedrectangular receptacle 10 is pro-,

vided and this receptacle has end walls 10a, side walls 10b, and abottom 100. A vertical partition 11, rising a short distance above thebottom 10c of the receptacle, extends longitudinally of the receptacle10 from one end wall 10a to the other end wall 10a, the lower edge ofthe partition 11 being secured to the bottom 100 in a medial locationwith respect to the side walls 10!: and the respective ends beingsecured to the end walls 10a. A horizontal partition 12 extends from theupper edge of the vertical partition to one of the side walls 10!) andfrom one of the end walls 10a to the other. the edges of the par ition12 being respectively secured to the elements between which thepartition extends. The partitions 11 and 12 form a compartment orchamber 13. Near each end of the chamber 13 the horizontal partition,forming the top thereof, is provided with a very small aperture 14, thechamber being entirely sealed except for the apertures 14.

A pair of vertically spaced rectangular plates or electrodes 15 and 16,formed of electrical conducting material are disposed, one above theother, within the chamber 13 in spaced relation to the walls thereof.The electrodes 15 and 16 are supported and secured in place by blocks1'7, formed of insulating material, respectively abutting the end wallsand the end portions of the side, top, and bottom walls of the chamber13, and having recesses in the inner sides thereof wherein therespective ends of the electrodes 15 and 16 are retained.

Electrical connection studs 18 and 19 are respectively secured at theirupper ends to the electrodes 15 and 18 and depend therefrom to a pointsomewhat below the bottom 100 of the receptacle l0 and chamber 13. Thestud 18, connected to the upper electrode 15 extends through a suitablylocated aperture in the lower electrode 16 and through an aperture inthe bottom 100 of the receptacle 10. The stud 19 extends through asecond aperture in the bottom 100, The stud 18 is provided with abushing 20' and a washer 22, formed of insulating material, to insulatethe same from the electrode 16 and the bottom 10c and to seal the studto the bottom where it passes therethrough. The stud 19 is provided witha bushing 21 and a washer 22, formed of insulating material, to insulatethe stud from and seal the same to the bottom 100. On each of therespective studs, a washer 23 and two nuts 24 are placed below thewasher 22. A pair of electrical conductors 25, adapted to be connectedto a source of electrical energy, are secured and electrically connectedto the respective studs 18 and 19 by means of the nuts 24.

A depending U-shaped support 26 is secured at its free ends to each endportion of the bottom 10c of the receptacle as shown. A cover consistingof a plate 2'? having an upstanding handle 27a secured to the centralportion thereof and a continuous depending flange 27b adjacent the edgesthereof is provided for the open top of the receptacle 10.

If desired the interior of the chamber 13 may be coated with electricalinsulating material. Also the exterior of the receptacle 10 may bejacketed with heat insulating material.

In use, the receptacle of my device is filled with water at least to alevel above that of the horizontal partition 12. Water will then passthrough the apertures 14 and fill the chamber 13 immersing theelectrodes 15 and 16. The electrodes are then connected to a source ofelectrical energy by means of the wires 25 and an electrical currentwill ,flow from one electrode to the other through the water in whichthey are immersed. The flow of current through the resistance of thewater will generate heat which will rapidly raise the temperature of thewater in the chamber 13 and heat will flow from the water in the chamberthrough the partitions 11 and 12 to the main body of water in thereceptacle 10 to simultaneously raise the temperature thereof.

As the water in the chamber becomes heated to the boiling point it willbe converted to steam and a small portion of the steam generated willescape through the small apertures 14 to carry additional heat to themain body of water. The steam flowing out of the chamber through theapertures 14 will prevent the entrance of water into the chamber throughthe apertures.

As more and more of the water in the chamber is converted into steam thewater level within the chamber will fall until it reaches a level atwhich it will make only imperfect contact with the upper electrode. Withsuch imperfect contact the fiow of electrical current and the productionof heat will be only suflicient to maintain the water in the device atsubstantially boiling temperature.

Should the temperature of the water in the device be reduced to belowthe boiling point, as through absorption of heat by cold water addedthereto or cold articles immersed therein, the steam in the chamber willrapidly condense, the outward flow of steam through the apertures 14will cease and water will immediately enter the chamber to raise thewater level therein to a point at whichthe electrodes will be immersed.With the electrodes immersed, the flow of electrical current and theproduction of heat will attain their full rates and the temperature ofthe water in the chamber will be rapidly brought back to the boilingpoint.

Obviously, if the water evaporates away to such an extent that the waterlevel in the chamber can no longer reach the upper electrode, noelectrical current will flow and the production of heat will cease, thusautomatically protecting the device from damage in the event that thedevice is inadvertently left connected to a source of electricitywithout the water level therein being maintained within normal operatingrange.

Another form of my invention, shown in Fig. 4, includes a tank 28 fromthe central portion of the top of which a' tube 29 extends downwardly toa level only slightly above the bottom thereof. A raised or bossedportion 30 of the top of the tank disposed above the tube 29 isapertured and the aperture is internally 'screw threaded as shown. Aflanged externally screw threaded plug 31, formed of electricalinsulating material, is threadedly engaged with the screw threadedaperture and a sealing gasket 32 is disposed between the flange portionthereof and the boss 30.

A pair of electrodes 33, formed of electrical conducting material, haveexternally screw threaded upper end portions 33a, which extendrespectively through each of a spaced pair of apertures through the plug31 and are held in place by nuts 34 to support the electrodes parallelto each other and in spaced relation within the tube 29. Two electricalconductors 35 are secured and electrically connected respectively to theprotruding portions of the screw threaded upper portions 3341-01? theelectrodes 33 by means of nuts 34.

A check valve, having means for connection of an air pump thereto, and apressure gauge, each of which may be of a conventional type, are mountedin internally screw threaded apertures in the top of the tank 28 asshown.

A steam discharge pipe 38 is threadedly engaged in an internally screwthreaded aperture in the plug 31, and runs to a closed chamber or otherclosed system (not illustrated) where the steam may be utilized.

At the lower portion of the side of the tank 28 a water supply pipe 39,having a normally closed \valve 40 connected therein, and beingconnected to a sourcev of water under pressure, isthreadedly engaged inan internally screw threaded aperture in the side of the tank. 1 Thisform of my invention is used when it is desired to utilize the steam ata certain pressure. In normal use water is admitted to the tank throughthe valve 40 to partially fill the tank. An air pump is connected to thecheck valve 36 and is utilized to produce an air cushion in the upperportion of the annular space between the tank 28 and the tube 29 and tobuild up in the tank the particular pressure at which it is desired tomaintain steam,'the pressure attained being indicated on the gauge 37.The electrodes 33 are connected to a source of electrical energywhereupon current passing between the electrodes through the water inwhich they are immersed will act to heat the water. When the waterwithin the tube 29 has reached the boiling point steam will accumulatein the upper end of the tube and force the water level in the tubedownwardly to decrease the electrode area immersed in the water andhence reduce the. flow of electrical current and the amount of heatproduced. When suflicient steam has been accumulated so that the steamwithin the tube 29 equalizes the pressure of air in the tank 28, thewater level will have been driven downwardly to the level of the lowerends of the electrodes with the result that the flow of electricalcurrent and the production of heat will have been reduced to negligiblevalues. The steam then at the desired pressure runs through the pipe 38to the point where it is utilized. If desired the pipe 38 may beprovided with a discharge outlet and steam at a desired pressure willrun through the pipe and discharge at the outlet.

If the quantity of steam in the upper portion of the tube 29 is reducedeither through condensationor through use of steam, the water level inthe tube 29 will be forced upwardly by the air cushion in the upperportion of the tank 28 and the electrodes will again be at leastpartially immersed. Electrical current will then flow between theelectrodes and produce heat to convert a portion of the water to steamand thus replace the steam which had been used or condensed. The steamwithin tube 29 will thus be constantly maintained at approximately adefinite pressure having but slight fluctuations. The water may, ofcourse, be replenished at any time by opening the normally closed valve40.

Still another form of my invention, shown in Fig. 5, includes a tank 41similar to the tank 28 of Fig. 4. A tube 42 is attached at its upper endto the top of the tank 41 in the same manner as the tube 29 of Fig. 4.The middle and lower portions of the tube 42 are of considerably reduceddiameter as shown and extend to a level only slightly above the bottomof the tank 41.

A plug 43, identical in construction with the plug 31 of Fig. 4, ismounted at the top of the tank 41 in the manner described in connectionwith Fig. 4. A pair of electrodes 44 depend from the plug 43 to a levelsomewhat above the level of the top of the reduced portion of the tube42.

A water inlet pipe 45 is connected to the lower portion of the tank 41and a water outlet pipe 46 is connected to the upper portion of thetank. An air release valve 4'7 is engaged in the threaded aperture inthe plug 43.

This form of my invention is used when it is desired to heat water insystems of piping such as water supply systems operating under pressure,hot water building heating systems, and

' others.

In normal use, the inlet pipe 45 is connected to the source of the waterto be heated and the outlet pipe 46 runs to the point or points at whichhot water is to be utilized.

When first filled with water and occasionally thereafter any airentrapped in the upper end of the tube 42 is released by temporarilyopening the normally closed air relief valve 47. Both the tank 41 andthe tube 42 will then be filled to the top with water.

When electrical energy is supplied to the electrodes 44 the water inwhich they are immersed will be heated in the manner previouslyexplained. The production of heat will be automatically regulated in amanner similar to that described in connection with Fig. 4 to maintainat all times a certain quantity of steam in the upper portion of thetube 42. Heat will be transmitted through the walls of the tube 42 fromthe steam and hot water therewithin to the water in the annular spacebetween the tank 41 and the tube 42. When hot water is drawn through theoutlet pipe 46 from the upper portion of the tank 41, cold water will bedelivered through the inlet pipe 45 to the lower portion of the tank toreplace the hot water which is removed. The cooler water will absorbheat rapidly enough to condense at least part of the steam in the upperpart of the tube 42 and hence permit the water to rise in the tube toimmerse the electrodes 44 and thereby cause production of heat toproduce steam and to again bring the water in the tank up to normaltemperature.

In all three of the forms of my invention shown it is obvious that lackof water will stop the flow of electrical current and the production ofheat rather than to cause damage to the device. Any of the forms showncan be operated on either alternating or direct current but it issomewhat preferable to use alternating current in order to minimize theeflects of electrolysis on the electrodes.

It is apparent that I have invented a novel, inexpensive, eflicient, andcompact electrically operated water heating device wherein theconsumption of electrical energy and the production of heat areautomatically regulated to maintain the water temperature substantiallyat the boiling point or steam at substantially constant pressure, andwherein shortage of water will stop the consumption of electrical energyand the production of heat.

It will, of course, be understood that various changes may be made inthe form, details, arrangement and proportions of the various partswithout departing from the scope of the present invention.

What is claimed is:--

1. In an electrical water heater, a receptacle adapted for holdingwater, a chamber formed in the lower portion of said receptacle, therebeing a small perforation in the upper portion of the walls of saidchamber to provide a restricted passage between the interior of saidchamber and the interior of said recep'acle, said chamber, with theexception of said perforation, being entire'y closed, a pair ofelectrodes located within said chamber, and means connecting saidelectrodes to a source of electrical energy.

2. In an electrical water heater, an open topped receptacle adapted forholding water, partitions connected to the lower portion of saidreceptacle to form in conjunction therewith a chamber, said partitionsbeing provided with an aperture communicating with said chamber in theupper portion thereof and said chamber otherwise being entirely closed,a pair of electrodes located within said chamber, and means forconnecting said electrodes to a source of electrical energy.

3. In an electrical water heater, an' open topped receptacle adapted forholding water, partitions connected to the lower portion of saidreceptacle to form in conjunction therewith a chamber, said partitionshaving a small aperture in the upper portion thereof to provide arestricted passage between the respective interiors of said chamber andsaid receptacle and said chamber otherwise being completely closed, apair of electrodes located within said chamber, and means for connectingsaid electrodes to a source of electrical energy.

OTTO A. LENZ.

